United Nations human rights investigators have tabled a report on conditions in at least four large prison camps they say are known to exist in North Korea today.

Their findings include unprecedented public testimony by defectors at hearings held in South Korea, Japan, Britain and the United States.

The inquiry covered food deprivation, torture, executions, abductions and rape. These were identified as tools for controlling the population.

Amnesty International released video of North Koreans who spoke about experiencing the horrors of the regime.

Kim Young Soon, who was imprisoned in Yodok camp for nine years, said: “You work from sunrise to sunset, rising at half past three and then working till dark. There is a guilt-by-association system. If I have committed an offence, the rest of my family are forced to go with me to the prison camp – without knowing the charge.”

The report details brutal abortions which are often fatal; women are systematically subjected to rape by guards or bought and sold by traffickers in China.

Former prison camp inmate Jihyum Park said: “In Onsung, women are blood tested for pregnancy and sexually transmitted disease. They force abortion after the test. Pregnant women in labour camps also carry loads up and down hills, to cause miscarriages.”

A former army officer, Joo-Il Kim, talked about leaders’ low priority given to feeding people: “The shortage of food is the biggest problem in the North Korean military. Civilians and the military suffer. Starvation is the biggest problem.”

The report said North Koreans who are forcibly repatriated – having fled to China – are commonly subjected to torture, arbitrary detention and summary execution.

Amnesty has long asked for cooperation from Pyongyang ally Beijing.

Roseann Rife, East Asia Director at Amnesty International, said: “What we need is for China to not obstruct any action that might take place at the Security Council, and also to take its responsibility seriously in protecting the human rights of North Koreans who cross over into China, by not returning them to North Korea.”

The report says there were 12 camps or more in the past.

Drawings of camp suffering are on display in South Korea. The North effectively denies the renderings, and the report, as imaginary.